In a Wall Street Journal op-ed offering advice to President-elect Obama, Chao warned that the Labor Department could be used to “harm American worker competitiveness through misguided regulations and punitive policies.”

At the top of the list of such ill-advised policies, Chao wrote, is card-check. It would replace the current system of secret balloting over union representation with a new system of public balloting.

Making the vote of every worker public, opponents worry, would open the door to intimidation tactics by union toughs.

Former Democratic presidential candidate George McGovern has also sharply criticized card check, which is included in the Employee Free Choice Act that nearly passed the last session of Congress. It died following a Republican filibuster, but is expected to come up for a vote again this year.

The BarackObama.com Web site states: “Obama cosponsored and is strong advocate for the Employee Free Choice Act, a bipartisan effort to assure that workers can exercise their right to organize. He will continue to fight for EFCA's passage and sign it into law.”

Chao called card check a counterproductive, special-interest initiative.” She also warned it will subject employees to “solicitation and potential intimidation.”